new SourceDescription(GwtSource.class, GwtSourceNewComposite.class);
editableSupport.addSource(editableSource, sourceDescription, parameters);
}
// do externalize
StringPropertyInfo propertyInfo = editableSupport.getProperties(frame).get(0);
editableSupport.externalizeProperty(propertyInfo, editableSource, true);
// apply commands
support.applyEditable(editableSupport);
// checks
assertEditor(
"public class Test implements EntryPoint {",